1. Field of the Invention
The present invention relates to the pre-vaporization of fuel for internal combustion engines. In a conventional engine, air and fuel in the form of vapor, and in a suitable ratio, are passed into the cylinders of the engine. Heat for the vaporization of this fuel is traditionally provided by the engine itself. For example, in an ordinary gasoline engine, the intake manifold is disposed adjacent the exhaust manifold so that heat from the latter will cause vaporization of the fuel in the former before it reaches the cylinders.
As is well known in the art, the more complete the vaporization of the fuel, the greater the effeciency of the engine. In conventional engines, however, complete, uniform vaporization is rare. The consequence is incomplete combustion of the fuel resulting in low efficiency and a relatively high amount of pollutants. In an effort to combat this problem, additives are often mixed with the fuel to increase its efficiency. However, such additives cause the production of even more pollutants.
2. Description of the Prior Art
Several prior art systems have been proposed for pre-vaporization of the fuel prior to its entry into the intake manifold of an engine in order to provide for more complete combustion of the fuel. For example, U.S. Pat. No. 3,498,279 to Seeley teaches passing raw gasoline over a hot surface prior to introduction into the carburetor of a standard internal combustion engine or the cylinder of a diesel engine. The surface is heated either by an electrically operated heater or a gas heated countercurrent exchanger employing the hot gaseous products of combustion. U.S. Pat. No. 3,952,716 to McCauley discloses a system in which a fuel/air mixture is oscillated by means of a rotor, subjected to sonic vibration and then passed through a heated grid or screen to promote vaporization. U.S. Pat. No. 3,973,543 to Nakada discloses a system for promoting vaporization of fuel within the intake manifold of an engine by means of an intensive electric field.
None of the above systems, however, have been entirely satisfactory. For example, various ones of them are too slow in heating and vaporizing the fuel, too complicated, and/or tend to produce waste products of their own.